1. Field of the Invention
The present invention relates to a mold-in fastening member to be fixed to the surface of a molded resin article, such as automotive seat cushions and office chair cushions. The molded resin article with the mold-in fastening member is made into seats, etc. by fixing an upholstery material, such as fabric or similar, to the surface of the molded resin article through the mold-in fastening member.
2. Discussion of Background
A new molding method has recently been proposed for the production of an automotive seat. This method involves the steps of: placing a fastening member, having a large number of engaging elements on its top surface and a large number of anchoring elements on its back surface, i.e., a flat fastener tape, in position within a mold; injecting a foamable resin into the mold; and expanding the foamable resin such that the anchoring elements are embedded into a molded resin article to integrally bind the molded resin article and the flat fastener tape and the engaging elements are bared or exposed on its outer surface (i.e., so-called mold-in forming method). The molded resin article is covered along its contour with a seat cover (i.e., upholstery material) by the engaging function between the engaging elements on the back surface of the seat cover and the engaging elements of the flat fastener tape.
In the mold-in forming method, a fastening member is held in place within a mold by fitting it into a recess formed at a given position of the mold with its surface having engaging elements facing the bottom of the recess and then, a resin is cast into the mold while keeping the fastening member in position to perform the molding. In performing the mold-in forming method with the fastening member fitted into the recess of the mold, a liquid foamable molding resin (hereinafter may be referred to as “resin”) injected into the mold may enter into the side of the fastening members through gaps between the fastener member and the recess of the mold, thereby burying the engaging elements in the resin. Since the engaging elements buried in the resin no longer have the engaging function, the infiltration of the resin through the gaps between the fastener member and the recess of the mold should be prevented. More specifically, since the fastening member is usually of an elongated rectangular shape, i.e., a tape-like shape, the infiltration of the molding resin occurs at gaps between the lateral edges of the fastening member and the recess, particularly the shoulders of the recess, and gaps between the longitudinal edges of the fastening member and the edges (shoulders) of the recess. Since the infiltrated resin buries the engaging elements held in the recess, the engaging elements that are intended to be exposed to the surface of the molded resin article are no longer exposed because of the covering resin.
A conventional method for solving the above-described problems is shown in FIG. 3. A fastening member (A) comprises a flat fastener tape (E), a steel strip (F), and a cover film (G). The flat fastener tape (E) has a substrate (B) having a large number of engaging elements (C) on its top surface and a large number of anchoring elements (D) on its back surface. The steel strip (F) under the engaging elements (C) is magnetically attached to a magnet (J) embedded in the bottom of a mold during the mold-in process. The cover film (G) entirely covers the steel strip (F) and the engaging elements (C) to prevent a molding resin composition from entering into the side of the engaging elements (C) during the mold-in process. The outer periphery of the cover film (G) is integrally bonded to the periphery of the flat fastener tape (E) by an adhesive or heat sealing.
The fastening member (A) is fixed in a recess (K) of the mold by the magnetic force exerted on the steel strip (F) by the magnet (J) disposed at the bottom of the mold with the engaging elements (C) facing the bottom of the recess (K). Then, a foamable resin is injected into the mold to produce a molded article, such as a cushion, in which the anchoring elements (D) are embedded. After taking the molded article out of the mold, the cover film (G) and the steel strip (F) are removed to allow the engaging elements (C) of the flat fastener to be bared or exposed on the surface of the molded article.
However, after the production of the molded article, the above-described mold-in forming method requires the removal of the steel strip (F) and the cover film (F) which should be disposed of as waste. In addition, the cover film (G) should be removed with great care to make the removing operation troublesome because film residues on the engaging surface, if any, prevent the exposure of the engaging elements (C) to result in a reduced engaging force and poor appearance. Thus, the removing operation is labor-intensive and the removal of the steel strip (F) has a risk of injuring fingers or hands.
Japanese Patent Application Laid-Open No. 1-113214 (hereinafter “JP '214”) and Japanese Patent Application Laid-Open No. 5-16173 (hereinafter “JP '173”) each disclose fastening members comprising a flat fastener and a foamed resin bonded to each other. In JP '214, a flexible foam and a flat fastener having engaging elements are bonded to each other through a magnetic film, with the surface of the magnetic film that faces the flat fastener exposed around the periphery of the flat fastener. The magnetic film is magnetically attached at its exposed peripheral surface to magnets provided at shoulders of a recess in a mold, thereby preventing gaps from being formed. However, since the magnetic film is disposed between the flexible foam and the flat fastener, the entire part of the fastening member falls or is difficult to be efficiently fitted into the recess because of a weak magnetic attraction force. Further, it is difficult to provide magnets in the narrow space of the recess shoulder, making the proposed method difficult to put into practice.
In JP '173, a flat fastener and a foamed body having a width and a height relatively larger than those of the flat fastener are bonded to each other to form a fastening member, which is inserted into a hollow space surrounded by a raised wall formed in a mold. Therefore, the fastening member has a considerably large size and is difficult to handle. Also, a fastening member having a foamed body with a large contact resistance to the raised wall cannot be easily inserted in position.
Japanese Patent Applications Laid-Open No. 7-148007 (hereinafter “JP '007”) discloses a mold-in fastening member having a substrate provided on its front surface with engaging elements and on its rear surface with fitting elements raised from the lateral edge portions and extending along the longitudinal direction. In JP '007, the head portion of the fitting elements projects outwardly from the lateral edges to leave no gap between the lateral edges of the fastening member and the recess of a mold.
Since the above fastening member is push-fitted into the recess, care must be paid to ensure a close contact between the fitting elements and the side wall of the recess. If loosely fitted, gaps are left to allow the resin to flow into the recess. Further, the proposed method is applicable only to the production of fastening members having linear shapes, but substantially inapplicable to the production of fastening members having curved shapes.